Systems and methods for cooling of power electronic devices

ABSTRACT

The invention provides systems and methods for cooling of power electronic devices with an optimized electromechanical structure. A power electronic device may comprise one or more power transistor components, one or more capacitor components, one or more power interconnect components that may be in electrical communication with the one or more power transistor components and the one or more capacitor components, and one or more heat sink components. The one or more power transistor components and the one or more capacitor components may be in thermal communication with the one or more heat sink components, and each may be located on substantially opposite sides of the one or more heat sink components, such that heat may be transferred from the one or more power transistor components and the one or more capacitor components to the same one or more heat sink components.

CROSS-REFERENCE

This application is a Continuation Application which claims the benefitof U.S. application Ser. No. 15/340,336, filed Nov. 1, 2016, whichclaims the benefit of U.S. application Ser. No. 14/115,863 filed Jun.30, 2014, now U.S. Pat. No. 9,516,789, issued Dec. 6, 2016, which is a371 application which claims the benefit of PCT Application No.PCT/US11/52074, filed Sep. 19, 2011, which claims the benefit of U.S.Provisional Application No. 61/482,878, filed May 5, 2011, all of whichis incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

Power electronic devices have limitations due to the overheating ofinternal components. The electromechanical structure of the internalcomponents of power electronic devices is also an important factor thatmay affect electrical and thermal performance. A desire exists tominimize the size and weight of power electronic devices, especially inmobile applications, such as electric and hybrid electric vehicles. Withimproved cooling of internal components, it is possible to design apower electronic device to produce higher power in a more compact andlower weight package as compared to traditional designs. The improvedcooling may facilitate increasing the operating current of the internalcomponents, which may translate directly into higher power, andconsequently higher power density of the power electronic device. Theimproved cooling may also provide for greater thermal operating headroomfor the internal components, which may translate into higher reliabilityof the internal components, and thus higher reliability of the powerelectronic device overall. Concurrently optimizing the electromechanicalstructure of the internal components of the power electronic device mayalso provide for improved electrical and thermal performance in a morecompact and lower weight package, also contributing to higher powerdensity.

Thus, a need exists for improved systems and methods for powerelectronic devices, which may provide improved cooling for criticalinternal components of power electronic devices, and concurrently mayprovide an optimized or improved electromechanical structure for theinternal components, enabling high reliability and high power density.

SUMMARY OF THE INVENTION

The invention provides systems and methods for cooling of powerelectronic devices with an optimized electromechanical structure.Various aspects of the invention described herein may be applied to anyof the particular applications set forth below or for any other types ofpower electronic devices. The invention may be applied as a standalonesystem or method, or as part of an integrated system, such as in avehicle. It shall be understood that different aspects of the inventioncan be appreciated individually, collectively, or in combination witheach other.

An aspect of the invention may be directed to a power electronic devicecomprising one or more power transistor components, one or morecapacitor components, one or more power interconnect components that maybe in electrical communication with the one or more power transistorcomponents and the one or more capacitor components, and one or moreheat sink components. The one or more power transistor components andthe one or more capacitor components may be in thermal communicationwith the one or more heat sink components, and each may be located onsubstantially opposite sides of the one or more heat sink components,such that heat may be transferred from the one or more power transistorcomponents and the one or more capacitor components to the same one ormore heat sink components.

A method for cooling a power electronic device may be provided inaccordance with another aspect of the invention. The method may compriseproviding one or more power transistor components, one or more capacitorcomponents, one or more power interconnect components that may be inelectrical communication with the one or more power transistorcomponents and the one or more capacitor components, and one or moreheat sink components, wherein the one or more power transistorcomponents and the one or more capacitor components may be in thermalcommunication with the one or more heat sink components. The method mayalso include locating the one or more power transistor components andthe one or more capacitor components on substantially opposite sides ofthe one or more heat sink components, such that heat may be transferredfrom the one or more power transistor components and the one or morecapacitor components to the same one or more heat sink components,thereby cooling the one or more power transistor components and the oneor more capacitor components.

Other goals and advantages of the invention will be further appreciatedand understood when considered in conjunction with the followingdescription and accompanying drawings. While the following descriptionmay contain specific details describing particular embodiments of theinvention, this should not be construed as limitations to the scope ofthe invention but rather as an exemplification of preferableembodiments. For each aspect of the invention, many variations arepossible as suggested herein that are known to those of ordinary skillin the art. A variety of changes and modifications can be made withinthe scope of the invention without departing from the spirit thereof.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1A shows internal components of a power electronic device inaccordance with an embodiment of the invention.

FIG. 1B shows an alternate view of the internal components of a powerelectronic device in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

While preferable embodiments of the invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention.

FIG. 1A shows internal components of a power electronic device inaccordance with an embodiment of the invention. In some embodiments ofthe invention, the power electronic device may be a power converter,such that the device may function, for example, to convert DC power toAC power, AC power to DC power, DC power to DC power at a differentvoltage or varying voltages, or AC power to AC power at a differentvoltage and/or frequency or varying voltages and/or frequencies, or anycombination thereof. For example, in some embodiments, the powerelectronic device may be a three-phase variable frequency AC inverterthat may be used to drive an AC electric machine. Examples of an ACelectric machine may include a motor, generator, or any sort of machinethat may require some form of AC electric power for operation.Alternatively, the power electronic device may be any type of powerconverter, inverter, rectifier, or any type of device that may includesome form of power transistor component and some form of capacitorcomponent, and may require some form of cooling and/or electrical andmechanical interconnection for those components.

The power electronic device may be utilized in a system. For example,the device may be used in a vehicle, such as an automobile, motorcycle,truck, van, bus, or other type of passenger, commercial, or industrialvehicle, train or other type of railed vehicle, watercraft, aircraft, orany other type of vehicle, or other type of commercial or industrialmachinery or equipment.

The power electronic device may operate at high current levels, and mayproduce higher power than conventional devices of the same size andweight. For example, the power electronic device may operate at currentsof about 50 A, 100 A, 200 A, 500 A, or 1,000 A or more and may producepower of about 20 kW, 50 kW, 100 kW, 200 kW, or 500 kW or more. Theintegrated cooling and electromechanical structure may enable higherpower density of the power electronic device by providing for cooling ofthe critical internal components, as well as increasing or optimizingthe performance and packaging density of the electrical and mechanicalinterconnections.

FIG. 1B shows an alternate view of the internal components of a powerelectronic device with an electromechanical structure and cooling methodin accordance with an embodiment of the invention. The internalcomponents of a power electronic device may comprise one or more powertransistor components 1, one or more capacitor components 2, one or morepower interconnect components 3 that may be in electrical communicationwith the one or more power transistor components 1 and the one or morecapacitor components 2, and one or more heat sink components 4. The oneor more power transistor components 1 and the one or more capacitorcomponents 2 may be in thermal communication with the one or more heatsink components 4. The one or more power transistor components and theone or more capacitor components may or may not directly contact the oneor more heat sink components.

In one example, the one or more power transistor components may have asurface that contacts a surface of the one or more heat sink components.The power transistor component surface and the heat sink componentsurface may be complementary in shape. For example, both the powertransistor component surface and the heat sink component surface may besubstantially flat, and may provide a robust thermal connection.Likewise, the one or more capacitor components may have a surface thatcontacts a surface of the one or more heat sink components. Thecapacitor component surface and the heat sink component surface may becomplementary in shape. For example, both the capacitor componentsurface and the heat sink component surface may be substantially flat,and may provide a robust thermal connection.

In another example, the one or more power transistor components may havea surface that may contact a surface of one or more intermediatecomponents, and the one or more intermediate components may have asurface that may contact a surface of the one or more heat sinkcomponents. The one or more intermediate components may or may not beconstructed of a material of high thermal conductivity. Furthermore, theone or more intermediate components may or may not be constructed of amaterial of high electrical conductivity. In some instances, thematerial may be an electrically insulating material. The one or moreintermediate components may be configured to provide high or maximizedthermal conductivity between the one or more power transistor componentsand the one or more heat sink components. Similarly, the one or morecapacitor components may have a surface that may contact a surface ofone or more intermediate components, and the one or more intermediatecomponents may have a surface that may contact a surface of the one ormore heat sink components. The one or more intermediate components mayor may not be constructed of a material of high thermal conductivity.Furthermore, the one or more intermediate components may or may not beconstructed of a material of high electrical conductivity. In someinstances, the material may be an electrically insulating material. Theone or more intermediate components may be configured to provide high ormaximized thermal conductivity between the one or more capacitorcomponents and one or more heat sink components.

In some embodiments, substantially no gaps or spaces may be providedbetween a heat sink component and an intermediate component, powertransistor component, and/or capacitor component. For example, in someinstances, substantially no gaps or spaces are provided between a powertransistor component and a heat sink component, and/or between acapacitor component and a heat sink component. In some instances, nointermediate components are provided between the power transistorcomponent and the heat sink component, and/or between the capacitorcomponent and the heat sink component. In other instances, one or moreintermediate components may be provided between the power transistorcomponent and the heat sink component, and/or between the capacitorcomponent and the heat sink component. The one or more intermediatecomponents may assist with heat transfer between the power transistorcomponent and the heat sink component, and/or between the capacitorcomponent and the heat sink component. For example, the one or moreintermediate components may comprise some type of thermal interfacematerial, such as a thermal paste or a thermal pad. The one or moreintermediate components may have low electrical conductivity. Forexample, the electrical conductivity of the one or more intermediatecomponents may be lower than the electrical conductivity of a materialforming a power interconnect component. In some cases, the one or moreintermediate components may comprise one or more power interconnectcomponents. Alternatively, the one or more intermediate components maynot comprise one or more power interconnect components.

A power transistor component surface may directly contact a heat sinkcomponent surface, such that a large portion of the surface area of thepower transistor component that is facing the heat sink componentcontacts the heat sink surface. For example, greater than 50%, 60%, 70%,80%, 90%, 95%, 99%, 99.5%, or 99.9% of the power transistor componentsurface that is facing the heat sink component may contact the heat sinksurface or be configured to contact the heat sink surface. One or moreintermediate components located between the power transistor componentsurface and the heat sink component surface that may assist with heattransfer between the power transistor component and the heat sinkcomponent may be considered integral to the power transistor componentand/or the heat sink component, such that the power transistor componentmay be considered to directly contact the heat sink. Similarly, acapacitor component surface may directly contact a heat sink componentsurface, such that a large portion of the surface area of the capacitorcomponent that is facing the heat sink component contacts the heat sinksurface. For example, greater than 50%, 60%, 70%, 80%, 90%, 95%, 99%,99.5%, or 99.9% of the capacitor component surface that is facing theheat sink component may contact the heat sink surface or be configuredto contact the heat sink surface. One or more intermediate componentslocated between the capacitor component surface and the heat sinkcomponent surface that may assist with heat transfer between thecapacitor component and the heat sink component may be consideredintegral to the capacitor component and/or the heat sink component, suchthat the capacitor component may be considered to directly contact theheat sink. In some embodiments, substantially all of a power transistorcomponent surface that is facing the heat sink component may directlycontact the heat sink, and/or substantially all of a capacitor componentsurface that is facing the heat sink component may directly contact theheat sink.

The one or more power transistor components 1 and the one or morecapacitor components 2 may be located on substantially opposite sides ofthe one or more heat sink components 4, such that heat may betransferred from the one or more power transistor components 1 and theone or more capacitor components 2 to the same one or more heat sinkcomponents 4, thereby cooling the one or more power transistorcomponents and the one or more capacitor components. In someimplementations, the one or more power transistor components and the oneor more capacitor components do not directly contact one another, butare each in simultaneous thermal communication with the one or more heatsink components. Furthermore, the one or more power transistorcomponents and the one or more capacitor components may each be insimultaneous thermal communication with the same one or more heat sinkcomponents. Additionally, the one or more power transistor componentsand the one or more capacitor components may each be in simultaneousdirect physical contact with the same one or more heat sink components.

A heat sink component may have a first side and an opposite orsubstantially opposite second side. In some instances, the first andsecond side may be substantially parallel. In other instances, the firstand second side may be oriented at an angle, which may include but isnot limited to a 1 degree angle, 5 degree angle, 10 degree angle, 15degree angle, 30 degree angle, 45 degree angle, 60 degree angle, 75degree angle, 80 degree angle, 85 degree angle, or 89 degree angle. Oneor more power transistor components may be in thermal communication withthe heat sink through the first side. One or more capacitor componentsmay be in thermal communication with the heat sink through the secondside. A heat sink may have a third side, a forth side, or any number ofadditional sides connecting the first and second sides. In someimplementations, the third side, the forth side, or the any numbers ofadditional sides do not have power transistor components or capacitorcomponents thereon. Alternatively, the third side, the forth side, orthe any number of additional sides may have one or more power transistorcomponents and/or one or more capacitor components thereon, in additionto or in place of the one or more power transistor components that maybe in thermal communication with the first side or the one or morecapacitor components that may be in thermal communication with thesecond side.

In some embodiments, the one or more power interconnect components 3,which may be in electrical communication with the one or more powertransistor components 1 and the one or more capacitor components 2, maybe constructed of a material with high electrical conductivity, such ascopper, which may enable the transmission of high electrical currentwith low resistive loss. Additional examples of such material mayinclude other metals, such as aluminum, brass, silver, gold, iron,steel, tin, or lead, or any other electrically conductive materials, orany alloys, mixtures, or combinations thereof. The one or more powerinterconnect components 3 may also be configured such that theinductance in the electrical transmission circuit between the one ormore capacitor components 2 and the one or more power transistorcomponents 1 is low or minimized.

The one or more power interconnect components may or may not directlycontact the one or more power transistor components or the one or morecapacitor components. In some instances, the one or more powerinterconnect components may contact the one or more power transistorcomponents through one or more electrically conductive intermediatecomponents or materials. Similarly, in some instances, the one or morepower interconnect components may contact the one or more capacitorcomponents through one or more electrically conductive intermediatecomponents or materials.

The one or more power interconnect components may or may not contact theone or more heat sink components. In one example, the one or more powerinterconnect components may contact the one or more power transistorcomponents and may contact the one or more capacitor components withoutcontacting the one or more heat sink components. Furthermore, the one ormore power interconnect components may contact the one or more powertransistor components on a side that is substantially opposite the sideof the one or more power transistor components that may be in thermalcommunication with the one or more heat sink components. Similarly, theone or more power interconnect components may contact the one or morecapacitor components on a side that is substantially opposite the sideof the one or more capacitor components that may be in thermalcommunication with the one or more heat sink components. The one or morepower interconnect components may have a configuration that wraps aroundthe one or more power transistor components and the one or morecapacitor components, such that the one or more power interconnectcomponents may simultaneously contact the one or more power transistorcomponents on a side that is substantially opposite the side that may bein thermal communication with the one or more heat sink components, andmay also contact the one or more capacitor components on a side that issubstantially opposite the side that may be in thermal communicationwith the one or more heat sink components. Alternatively oradditionally, the one or more power interconnect components may contactany one or more sides of the one or more power transistor componentsand/or may contact any one or more sides of the one or more capacitorcomponents.

In some instances, the one or more power interconnect components may notcontact the one or more heat sink components. The one or more powerinterconnect components may pass outside of and/or along one or moresides of a heat sink component without contacting the heat sinkcomponent. The one or more power interconnect components may or may notpass through a hole or opening in a heat sink component withoutcontacting the heat sink component. In some implementations, the one ormore power interconnect components may not pass through any portions ofthe one or more heat sink components. The one or more power interconnectcomponents may pass around and/or along the exterior of the one or moreheat sink components.

In another example, the one or more power interconnect components maycontact the one or more power transistor components and may contact theone or more capacitor components, and may also contact and/or be inthermal communication with the one or more heat sink components. The oneor more power interconnect components may contact the one or more powertransistor components on substantially the same side of the one or morepower transistor components that may be in thermal communication withthe one or more heat sink components, and the one or more powerinterconnect components may also contact and/or be in thermalcommunication with the one or more heat sink components. Similarly, theone or more power interconnect components may contact the one or morecapacitor components on substantially the same side of the one or morecapacitor components that may be in thermal communication with the oneor more heat sink components, and the one or more power interconnectcomponents may also contact and/or be in thermal communication with theone or more heat sink components.

The one or more power interconnect components may or may not directlycontact the one or more heat sink components. In some instances, the oneor more power interconnect components may have a surface that contacts asurface of the one or more heat sink components. The power interconnectcomponent surface and the heat sink component surface may becomplementary in shape. For example, both the power interconnectcomponent surface and the heat sink component surface may besubstantially flat, and may provide a robust thermal connection. A powerinterconnect component surface may directly contact a heat sinkcomponent surface, such that a large portion of the surface area of thepower interconnect component that is facing the heat sink componentcontacts the heat sink surface. For example, greater than 50%, 60%, 70%,80%, 90%, 95%, 99%, 99.5% or 99.9% of a power interconnect componentsurface that is facing a heat sink component surface may contact theheat sink surface or be configured to contact the heat sink surface. Insome embodiments, substantially no gaps or spaces may be providedbetween the power interconnect component surface and the heat sinkcomponent surface on a side of the heat sink component that is facingthe power transistor component. In other embodiments, substantially nogaps or spaces may be provided between the power interconnect componentsurface and the heat sink component surface on a side of the heat sinkcomponent that is facing the capacitor component. In other instances,the one or more power interconnect components may have a surface thatmay contact a surface of one or more intermediate components, and theone or more intermediate components may have a surface that may contacta surface of the one or more heat sink components. The one or moreintermediate components may or may not be constructed of a material ofhigh thermal conductivity. Furthermore, the one or more intermediatecomponents may or may not be constructed of a material of highelectrical conductivity. In some instances, the material may be anelectrically insulating material. The one or more intermediatecomponents may be configured to provide high or maximized thermalconductivity between the one or more power interconnect components andthe one or more heat sink components. One or more intermediatecomponents located between the power interconnect component surface andthe heat sink component surface that may assist with heat transferbetween the power interconnect component and the heat sink component,may be considered integral to the power interconnect component and/orthe heat sink component, such that the power interconnect component maybe considered to directly contact the heat sink.

In some embodiments, a power interconnect component may have one or morebends, curves, or folds. Any descriptions of bends may also apply tocurves or folds, or other surface features or shapes, and vice versa.For example, a power interconnect component may have a wraparoundconfiguration with two or more substantially perpendicular bends to forman angular C-shape. A power interconnect component may have a first bendalong one side of a heat sink, and a second bend along another side of aheat sink. A power interconnect component may have a first bend at ornear a side of a power transistor component that is substantiallyopposing a heat sink component, and/or a second bend at or near a sideof a capacitor component that is substantially opposing a heat sinkcomponent. The first and second bends may enable a power interconnectcomponent to wrap at least partially around a power transistor componentand a capacitor component. In some embodiments, at least a portion of apower transistor component, heat sink component, and/or capacitorcomponent may be located between portions of the power interconnectcomponent.

In some embodiments, the one or more power transistor components 1 maybe a power semiconductor module, such as an insulated gate bipolartransistor (IBGT) module. Alternatively, in other embodiments, the oneor more power transistor components may be any type of power transistorcomponent, device, or apparatus known in the art or later developed, orany configuration, variation, or combination thereof. Furthermore, theone or more power transistor components may have any physical form,structure, or configuration, and may comprise any type of packaging,enclosure, mountings, or connections.

In some examples, the one or more power transistor components 1 maycomprise one or more power transistor modules, wherein a plurality ofindividual power transistor devices may be packaged together in a singleenclosure. In other examples, the one or more power transistorcomponents may comprise one or more discrete power transistor devices,wherein single power transistor devices may be packaged separately inindividual enclosures. Furthermore, in some instances, the one or morepower transistor components may or may not additionally comprise anynumber of other types of devices along with the power transistordevices, such as diode devices, sensing devices, or any other types ofdevices or combinations thereof.

The power transistor devices may be any type of semiconductor device andmay comprise a semiconductor material such as silicon, germanium,silicon carbide, gallium arsenide, gallium nitride, or any other type ofsemiconducting material known in the art or later developed, or anycombination thereof. The power transistor devices may have any type oftransistor structure, such as a bipolar junction transistor (BJT),junction gate field-effect transistor (JFET), metal-oxide-semiconductorfield-effect transistor (MOSFET), insulated gate bipolar transistor(IGBT), or any other type of transistor structure known in the art orlater developed, or any combination thereof.

In some embodiments, the one or more capacitor components 2 may be afilm type capacitor, such as a polypropylene film capacitor.Alternatively, in other embodiments, the one or more capacitorcomponents may be any other type of film capacitor, such as a polyamidefilm, polycarbonate film, polyester film, polyimide film, polystyrenefilm, polysulfone film, or polytetrafluoroethylene (PTFE) filmcapacitor, or any other type of capacitor, such as paper, glass, mica,ceramic, aluminum oxide electrolytic, tantalum oxide electrolytic, oilfilled, vacuum, electric double-layer capacitor (EDLC), or any othertype of capacitive or electrical energy storage component, device, orapparatus known in the art or later developed, or any configuration,variation, or combination thereof. Furthermore, the one or morecapacitor components may have any physical form, structure, orconfiguration, and may comprise any type of packaging, enclosure,mountings, or connections.

In some embodiments, the one or more power interconnect components 3 maycomprise a power interconnect bus. The power interconnect bus mayelectrically communicate with the one or more power transistorcomponents 1 and the one or more capacitor components 2. In someinstances, the power interconnect bus may comprise two or moreelectrically conductive components. The two or more electricallyconductive components may or may not be separated by one or moreelectrically insulating components or materials. Furthermore, the two ormore electrically conductive components may or may not be configuredsuch that the capacitance of the electrical transmission circuit betweenthe one or more capacitor components 2 and the one or more powertransistor components 1 is within a desired range.

Alternatively, in other embodiments, the one or more power interconnectcomponents 3 may comprise any type of component, material, or apparatusthat may be capable of transferring electrical power between the one ormore power transistor components 1 and the one or more capacitorcomponents 2. Furthermore, the one or more power interconnect componentsmay have any physical form, structure, or configuration, and maycomprise any type of packaging, enclosure, mountings, or connections.For example, the one or more power interconnect components may includeor utilize one or more wires, strips, bars, plates, meshes, nets,blocks, or any configuration, variation, or combination thereof.

Additionally, the one or more power interconnect components 3 may or maynot be configured such that the one or more power interconnectcomponents are capable of transferring a specific amount of powerbetween the one or more power transistor components 1 and the one ormore capacitor components 2 while limiting the temperature of the one ormore power interconnect components to a desired rise above ambientconditions.

In some embodiments, the one or more heat sink components 4 may be acold plate type heat sink, which may be cooled by directing a fluid toflow through the heat sink, such that heat may be transferred from theheat sink to the fluid, thereby cooling the heat sink. Alternatively, inother embodiments, the one or more heat sink components 4 may be anytype of heat sink component, device, or apparatus known in the art orlater developed, such that the one or more heat sink components maytransfer heat from the one or more power transistor components 1, theone or more capacitor components 2, and/or the one or more powerinterconnect components 3 to the one or more heat sink components.Furthermore, the one or more heat sink components may have any physicalform, structure, or configuration, and may comprise any type ofpackaging, enclosure, mountings, or connections. In some instances, theone or more heat sink components may transfer heat from the one or morepower transistor components, the one or more capacitor components,and/or the one or more power interconnect components to ambient air orconditions. The ambient air or conditions may or may not have activelyflowing fluid. Passive or active heat transfer may occur.

The cooling fluid that may be directed to flow though the one or moreheat sink components may be any fluid known in the art. A fluid mayinclude a liquid or gaseous fluid. In some embodiments, the coolingfluid may be a gas, such as air; or a liquid, such as water, oil, or atype of liquid dielectric fluid; or a vapor or mist of any such fluids;or any other type of fluid. Any type of coolant known in the art orlater developed may be utilized. In some embodiments, a combination offluids may be provided. For instance, a solution comprised ofapproximately half water and half ethylene glycol or propylene glycolmay be used. A fluid may be selected according to desired thermal,electrical, chemical, or flow properties. For example, the fluid mayhave a specific heat within a desired range, or may be a fluid that iselectrically non-conductive with a resistivity above a desired value, ormay be a fluid that is chemically inert or reactive with regard tocomponents comprising the power electronic device, or may be a fluidwith a viscosity within a desired range.

The fluid supplied to the power electronic device may or may not bepressurized. In some instances, the fluid may be pressurized by apositive pressure source, such as a pump or compressor. The positivepressure source may be external to the device (e.g., on the inlet sideof the device), or may be part of the device. In other embodiments, thefluid may be pressurized by a negative pressure source, such as avacuum. The negative pressure source may be external to the device(e.g., on the outlet side of the device), or may be part of the device.In some instances, the pressure source may be integral to the powerelectronic device and may assist with the flow of fluid within thedevice. Any pressure differential may be created that may assist withfluid flow. Additionally, fluid flow may be assisted by gravity. In someinstances, fluid flow may be assisted by convection effects or othertemperature differentials.

In some examples, fluid may be contained within a heat sink component,and may flow within the heat sink component. Alternatively, fluid may beprovided to the heat sink from an external source. Fluid may exit theheat sink. Fluid entering and exiting a heat sink may be part of aclosed loop fluid handling system, or may be part of an open loopsystem. A heat sink component may have one or more internal conduitsthat may enable fluid to flow therein. A heat sink component may haveone or more channels or fins therein, may be formed of one or moreplates, may have a shell and tube configuration, or may have anyconfiguration or features, or may comprise any combination thereof.

An exposed surface of a heat sink component may have a desired materialproperty. In some embodiments, an exposed surface of the heat sinkcomponent may be a housing or enclosure that may contain fluid flowfeatures therein. In another example, an exposed surface of the heatsink component may be the outer surface of a thermal block, which may ormay not be solid. The exposed surface of the heat sink component may bethermally conductive. Preferably, the exposed surface of the heat sinkcomponent may have a high thermal conductivity. The exposed surface ofthe heat sink component may or may not have a high electricalconductivity. In some instances, the exposed surface of the heat sinkcomponent may have a low electrical conductivity or may be electricallyinsulating.

In some embodiments, contacting a power transistor component and acapacitor component to the same heat sink component may enable the heatsink component to cool both the power transistor component and capacitorcomponent simultaneously. This configuration may require fewercomponents than if additional heat sink components were utilized toprovide separate cooling through individual heat sink componentsdedicated to the power transistor component and to the capacitorcomponent. Directly contacting the power transistor component and/orcapacitor component to the heat sink component may enable effectiveand/or efficient transfer of heat from the power transistor componentand/or capacitor component to the heat sink component. Similarly,contacting the power transistor component and/or capacitor component tothe heat sink component through one or more thermally conductiveintermediate components may enable effective and/or efficient transferof heat from the power transistor component and/or capacitor componentto the heat sink component. Heat may be transferred from the powertransistor component and/or capacitor component to the heat sinkcomponent via conduction. Having a relatively large surface area contactbetween a power transistor component and/or capacitor component and aheat sink component may enable high or maximized rates of conductiveheat transfer.

The power electronic device configuration, in accordance with anembodiment of the invention, may enable the power electronic device tohave a relatively compact footprint area and/or package volume. Forexample, the power electronic device may have a footprint area ofgreater than, less than, and/or equal to about 100 cm², 200 cm², or 400cm². Furthermore, for example, the power electronic device may have apackage height of greater than, less than, and/or equal to about 10 cm,15 cm, or 20 cm.

All or part of the power electronic device may be surrounded by ahousing. The device housing may include any structure or component thatsurrounds all or part of the device for the purpose of containment,support, and/or protection, or any other similar functions. A structureor component may function as a device housing, or may comprise part of adevice housing, and may additionally perform other unrelated functions.The housing may surround all or part of a device assembly, or maysurround all or part of any of the individual components of the device.One or more individual structures or components surrounding all or partof one or more individual components of the power electronic device mayseparately function as device housings, and may also collectivelycomprise a device housing. It will be apparent to those skilled in theart that the device housing, referred to herein, may also be referencedby other terminology without departing from the description providedherein, including case, frame, enclosure, or other similar terms. Thedevice housing, as referred to herein, may collectively include any andall individual structures and/or components (e.g., a heat sink) that mayperform the function of containment, support, and/or protection, or anyother similar functions, for the power electronic device or any of theindividual components of the power electronic device. In someembodiments, all or part of the device housing may be fluid-sealed.

The power electronic device may utilize high power electricalconnections. Reliable high power connections may require low-resistanceelectrical contact with acceptable current density. Typical maximumcurrent densities in copper DC power connections may be on the order of2.2×10⁶ A/m². This may typically limit the temperature rise of theconnection to under 30° C. in ambient temperatures over 40° C. See e.g.,ANSI C37.20C-1974, IEEE standard 27-1974. In copper three-phase AC powerconnections, maximum peak current densities of 7×10⁶ A/m² havetraditionally been used in power electronic devices reliably.

It should be understood from the foregoing that, while particularimplementations have been illustrated and described, variousmodifications can be made thereto and are contemplated herein. It isalso not intended that the invention be limited by the specific examplesprovided within the specification. While the invention has beendescribed with reference to the aforementioned specification, thedescriptions and illustrations of the preferable embodiments herein arenot meant to be construed in a limiting sense. Furthermore, it shall beunderstood that all aspects of the invention are not limited to thespecific depictions, configurations or relative proportions set forthherein which depend upon a variety of conditions and variables. Variousmodifications in form and detail of the embodiments of the inventionwill be apparent to a person skilled in the art. It is thereforecontemplated that the invention shall also cover any such modifications,variations and equivalents.

What is claimed is:
 1. A power electronic device comprising: one or moreheat sink components; one or more power transistor components, whereinthe one or more power transistor components are in direct thermalcommunication with the one or more heat sink components by directlycontacting a first surface of the one or more heat sink components; oneor more capacitor components, wherein the one or more capacitorcomponents are in direct thermal communication with the one or more heatsink components by directly contacting a second surface of the one ormore heat sink components; and one or more power interconnect buses inelectrical communication with the one or more power transistorcomponents and the one or more capacitor components, wherein the one ormore power interconnect buses are not in direct contact with the one ormore heat sink components; and the one or more power interconnect busescontact the one or more power transistor components on a side that issubstantially opposite the side of the one or more power transistorcomponents that is in thermal communication with the one or more heatsink components.
 2. The power electronic device of claim 1 wherein theone or more power interconnect buses have one or more electricallyinsulating components that separate one or more electrically conductivecomponents of the one or more power interconnect buses.
 3. The powerelectronic device of claim 1 wherein the one or more power interconnectbuses are thermally insulated from the one or more heat sink components.4. The power electronic device of claim 1 wherein the one or more powerinterconnect buses contact the one or more capacitor components on aside that is substantially opposite the side of the one or morecapacitor components that is in thermal communication with the one ormore heat sink components.
 5. The power electronic device of claim 1wherein the first surface and the second surface are substantiallyopposite sides of the one or more heat sink components.
 6. The powerelectronic device of claim 1 wherein substantially no gap is providedbetween the one or more power transistor components and the one or moreheat sink components.
 7. The power electronic device of claim 1 whereinsubstantially no gap is provided between the one or more capacitorcomponents and the one or more heat sink components.
 8. The powerelectronic device of claim 1, wherein the one or more capacitorcomponents are in direct thermal communication with the one or more heatsinks.
 9. A method for cooling a power electronic device comprising:providing one or more power transistor components; providing one or morecapacitor components; providing one or more heat sink components,wherein the one or more power transistor components and the one or morecapacitor components are in direct thermal communication with the one ormore heat sink components, and wherein the one or more power transistorcomponents and the one or more capacitor components are each located onsubstantially opposite sides of the one or more heat sink components,such that heat is transferred from the one or more power transistorcomponents and the one or more capacitor components to the same one ormore heat sink components, thereby cooling the one or more powertransistor components and the one or more capacitor components; andproviding one or more power interconnect buses in electricalcommunication with the one or more power transistor components and theone or more capacitor components, wherein the one or more powerinterconnect buses are not in direct contact with the one or more heatsink components; and the one or more power interconnect buses contactthe one or more power transistor components on a side that issubstantially opposite the side of the one or more power transistorcomponents that is in thermal communication with the one or more heatsink components.
 10. The method of claim 9 wherein the one or more powerinterconnect buses are thermally insulated from the one or more heatsink components.
 11. The method of claim 9 wherein the one or more powerinterconnect buses contact the one or more capacitor components on aside that is substantially opposite the side of the one or morecapacitor components that is in thermal communication with the one ormore heat sink components.
 12. The method of claim 9 wherein the one ormore power interconnect buses have one or more electrically insulatingcomponents that separate one or more electrically conductive componentsof the one or more power interconnect buses.
 13. The method of claim 9wherein the one or more power transistor components have a surface thatcontacts a surface of the one or more heat sink components.
 14. Themethod of claim 9 wherein the one or more capacitor components have asurface that contacts a surface of the one or more heat sink components.15. The method of claim 9 wherein substantially no gap is providedbetween the one or more power transistor components and the one or moreheat sink components.
 16. The method of claim 9 wherein substantially nogap is provided between the one or more capacitor components and the oneor more heat sink components.